Cohesive, machineable doughs which can be sheeted, stretched, and cut into pieces may be produced at room temperature when the doughs possess a high content of wheat or other gluten containing flour. Starch-based compositions which have little or no gluten, such as potato flour or corn flour, when mixed with water do not form a dough at room temperature that is coherent and continuously machineable or sheetable. Machinability of doughs made from ingredients having little or no gluten may be improved by forming a dough under elevated temperature conditions, such as by steaming the ingredients as disclosed in U.S. Pat. Nos. 4,873,093 and 4,834,996 to Fazzolare et al.
U.S. Pat. Nos. 4,931,303 and 4,994,295 to Holm et al disclose that in the production of fabricated snack products having controlled surface bubbling, the dough sheet must have cohesive properties which permit the surface or surfaces of the dough or preform to stretch relatively uniformly when forming bubbles during frying. The highly cohesive, non-adhesive dough, it is disclosed, can be made by adjusting the quantity of free gelatinized starch, the degree of retrogradation of the starch (thereby affecting the water absorption of a given quantity of the starch) and the concentration of any starch-complexing emulsifiers present. In the Holm et al process, a dough may be formed comprising, e.g. potato solids or corn solids, raw or pre-gelatinized starches, modified starches, flavorings, oils, and the like. For producing potato snacks, the preferred major ingredient in the potato dough is a dehydrated potato flake with high water absorption capability. The dry ingredients are placed in a mixer and blended with water to obtain a dough having a moisture content of from about 30% to about 55% by weight. According to Holm et al, higher moisture content means higher oil absorption during frying. It is further disclosed that doughs containing less than about 30% moisture are generally too dry even after the Holm et al drying step to create adequate bubbles. In the Holm et al process, substantial moisture reduction of the dough is achieved by frying. During frying, the dough moisture content of about 30% to about 55% is reduced to obtain a fried product with a moisture content of about 1-2%.
U.S. Pat. No. 4,560,569 to Ivers discloses that in the production of a dough-based fried food product, a processed starch in either gelatinized or ungelatinized form is frequently added when a low starch flour or flake is employed. Water, it is disclosed, is required to soften the flour, and depending upon the protein content of the flour, to form a network of protein (gluten) which is the framework of the product. According to Ivers starch, which is present in flours, is used as a binder and is required for the unleavened product to expand upon frying. Dough stickiness and hardness of the cooked product may be controlled by the addition of oil to the dough to control the extent of the protein framework. The dough is prepared by adjusting the ratios of components and the mixing time to allow it to sheet uniformly at the desired thickness without sticking or tearing. According to Ivers, addition of a small amount of a lecithin-in-water suspension to the formulation of the dough-based fried snack foods improves the transfer, sheeting and cutting, and significantly reduces clumping during frying without the rapid buildup of free fatty acids and without significant darkening of frying oil normally associated with the frying of foods containing lecithin.
In the present invention, chip-like snacks having a crisp texture and chip-like appearance with blisters distributed over their surfaces are produced from coherent, machineable, sheetable doughs without using a frying step for substantial moisture reduction of the dough thereby resulting in products having low fat content. In addition, a machineable no- or low-gluten content dough may be produced at relatively low temperatures by the use of a pregelatinized waxy starch. When using a pregelatinized waxy starch to improve coherence and machinability of a no- or low-gluten content dough, efficient hydration of the pregelatinized waxy starch is achieved by preliminary mixing with part of the water, while admixing it with a portion of the low- or no-gluten content starchy material to aid dispersion and avoid clumping. The doughs may be sheeted continuously without tearing associated with uneven or non-homogeneous hydration of the pregelatinized starch.